Most times these little quakes are just releasing energy that otherwise would build up to a bigger quake. But sometimes they're transferring pressure from one part of the fault to another, which then triggers a big quake.
If you want scary, google the news about the quakes and other activity in Yellowstone, which could be a precursor to a "super eruption". If it happens it would wipe out 2/3 of the U.S.
I remember seeing a science show about the Yellowstone supercaldera on PBS, it said Yellowstone would take several decades (maybe up to a century) for the magma chamber to fill, with alot of EQs, geological deformaties, and possibly several smalller eruptions before going supernova, the upshot is that we should have a long warning time before the big one, lets hope so anyways...
never knew CA would look good compared to Colorado -but when you hear about yellowstone...
just pour a drink and watch the trains-your numbers up when its up
i went through what seemd to me a fairly big one in alaska when i was a legal extern in anchorage, was first quarter of 1980 -the entire building was moving, file cabinets swaying-felt like the deck of a ship in high seas-
the sour doughs who been through previosu quakes, including 64 moved so quickly to exit it was like a cartoon- iwas still figuring out what was happening as i watched